Method and apparatus for producing fibers



Oct. 22,. 1957 G. SLAYTER ETAL 2,310,157

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METHOD AND APPARATUS FOR PRODUCING FIBERS Filed March 5, 1952 Oct. 22,1957 10 Sheets-Sheet 7 I'll r A 57% s mmm N wmm 2 m 2 g Oct. 22, 1957'G. SLAYTER L 1 METHOD AND APPARATUS FOR PRODUCING FIBERS v Filed March5, 1952 l0 Sheets-Sheet 8 INVEN;FORS: FAA/r55 SLAYTER v E17 TDHE'ZZ. M;v 14 ATT RNEYS,

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if; TE'HER ATTQ NEYS Oct. 22, 1957 G. SLAYTE'R ET L 2,810,157.

METHOD AND APPARATUS FOR PRODUCING FIBERS Filed March 5, 1952 10Sheets-Sheet 10 INVENTORS FAMEE SLAYTER Y E17 FL mm.

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United States Patent METHOD AND APPARATUS FOR PRODUCING FIBERS GamesSlayter and Ed Fletcher, Newark, Ohio, assignors toOwens-Corning'Fiberglas Corporation, Toledo, 01110, a corporation ofDelaware Application March 5, 1952, Serial No. 274,912

24 Claims. (Cl. 182.5)

This invention relates to a novel method and apparatus for converting,reducing or changing materials to a finely divided state or condition,the method involving a novel utilization of forces acting on materialsin a manner to fiberize, atomize or otherwise effect changes in thephysical character or state of division of materials.

The invention relates more especially to a novel method and apparatusfor converting or changing flowable materials into fibers or to a stateof fine subdivision such as the conversion of heat-softenable mineralmaterials such as glass, fusible rock or slag to fine fibers, or forforming fibers from other materials such as fiber-forming resins or thelike, for atomizing liquids and for disintegrating other materials bytrituration through the application of forces in the manner of thepresent invention.

The present invention has been found to have particular utility inconverting bodies of glass to fine fibers and hence the detailedapplication of the method and apparatus for such purpose is hereinemphasized as a preferred example in carrying out the principles of theinvention which as hereinafter explained are readily applicable inprocessing other materials.

The formation of fibers from such materials as glass, fusible rock orslag, has been carried on commercially for several years and fibersformed from these materials have been utilized extensively for soundattenuation, heat insulation and other allied purposes as mineral fiberspossess many advantages over vegetable fibers. They are verminproof, arenot subject to deterioration under adverse weather conditions, areincombustible and hence are ideally suited in installations where theliability of fire presents a dangerous hazard.

Fibers for these purposes have been heretofore produced from minerals bydirecting blasts of steam or compressed air against a plurality of finestreams of molten mineral material, the steam or air blasts drawing outor attenuating the fine streams into fibers. Fibers formed by thisprocess are however comparatively coarse, of indiscriminate lengths andthe fibrous end product, such as a mat or bat, usually contains a highpercentage of shot or pellet formations of unfiberized material. In somecases, the percentage of shot by weight in the fibrous mass may be wellabove 40% and usually averages between 35% and 40%, depending upon theparticular operating conditions. The existence of pellets or unfiberizedmaterial in the end product serves no useful purpose as such pelletshave practically no insulating value and merely increase the shippingweight of mat structures formed of the fibers. Such processes have beenextensively used commercially because of the ability to attenuate alarge number of streams of glass by a single apparatus although thefibers are somewhat coarse in character.

Another method that has been utilized to some extent for producingfibers of much finer character than those produced by the steam or airblast method involves the use of a blast of intensely hot gases extrudedfrom a burner, the fiber-forming material being conveyed into the blastin a rod-like or rigid condition. A blast of this character is formed byprojecting exhaust or burned gases through a comparatively small orrestricted orifice in a wall of a burner in which a combustible mixtureis burned at a constant rate to produce a great expansion of the gasesresultingin an intensely hot, high velocity blast.

The rods or primary filaments of glass or the like conveyed or fed intoa blast of this character are softened and attenuated by the velocity ofthe blast to extremely fine fibers, the fibers being of an average sizeof from one-half to five microns in diameter. Due to certain limitationscharacteristic of this process, endeavors to increase the economicalproduction of fine fibers by attenuationrof primary filaments have notbeen entirely satisfactory. Attenuation of fibers by the use of a hotblast of gas has certain advantages in that the resulting productcontains a comparatively low percentage of unfiberized material orpellets as well as the attainment of a fluffy resilient fibrous mat offine fibers endowed with an improved insulating factor as compared withmats formed by the steam blast method. Methods have been exploreddirected to the utilization of a stream of molten glass fed directlyinto an intensely hot blast by utilizing differential pressure of acontrolled stream of air induced by the blast to cause the glass streamto enter the blast and therein attenuate to fibers, but methods of thischaracter have had only limited use because of the low fiber productionin proportion to the heat energy expended resulting in increased cost ofproducing fine fibers on a commercial scale. To obtain attenuated fibersthrough feeding a stream of molten material into a blast, it has beenheretofore essential to feed the stream in a manner providing a nub orinertia zone from which the gases moving at high velocity may draw thestream into fibers.

The present invention embraces a novel method involving a new principleof application of forces operative upon materials for producing finefibers wherein one or more streams of flowable fiber-forming material ofsubstantial size or volume may be converted or transformed into finefibers whereby a high rate of fiber production is obtained compared tothe energy input of the fiberforming forces.

An object of the invention involves the establishment and application offorces acting in diverse directions upon a body of material in such amanner that the body is broken up by the forces into particles orglobules which are immediately converted to fine fibers by the forces.

An objectof the invention resides in the provision of a method oftransforming or converting heat-softened materials to fiber form bysubjecting the softened materials to forces acting in differentdirections at velocities suificient to fiberize the materials with aminimum of unfiberized material in the end product.

Another object of the invention embraces a method of efiicientutilization of energy in the form of forces forming in effect forcecouples into which a flowable,

material is delivered whereby the velocities of the forces disintegrateor transform the material to a finely divided state or condition with ahigh degree of energy efiiciency.

An object of the invention resides in providing a plurality of streamsof gas moving at high velocities and flowing in an angular relationshipwhereby a body of softened fiber-forming material is acted upon by thestreams in a manner reducing the material to fine fibers of which asubstantial proportion is of a size one micron or less in diameter. 7

Another object of the invention resides in a method wherein a pluralityof gaseous streams moving at high velocities are arranged for traversein directions forming an X-pattern and includes feeding a body ofmaterial into the crossover zone of the blasts whereby the forces of theblast in angular relationship create a turbulence acting upon thematerial to reduce the same to fiber :form by attenuation, attrition orother disintegrating or fiberizing action.

A further object embraces a method of transforming material to a finelydivided conditioniorstate resulting in an end product comprising a massof comparatively fine fibers with a minor amount of unfiberized materialmost of which appearsin flake-likeparticlesand fine dustproviding afibrous mass of comparatively low density.

Another object embraces a method and apparatus especially usable for,fiberizing mineral material wherein the end product is inclusive of alarge percentage 'of very fine fibers of lengths sufficient to impart ahigh degree of resiliency to the fibrous mass.

Another object of the invention relates to the method of delivering astream of fiber-forming material into a zone of high velocity forces ina manner such that a coupling is established between the stream and theforces whereby under the influence of the forces the mechanicallyunstable stream is disintegrated or broken up into small bodies whichunder the influence of the forces are instantly attenuated or otherwiseformed into fibers.

Another object of the invention embraces a method of convertingfiber-forming material to fine fibers especially adaptable forlarge-scale production wherein large quantities of material are formedinto fibers in a minimum of time, the operation being continuous and theapparatus for carrying out the method requiring less space thanapparatus heretofore used for securing a comparable yield of coarsefibers.

Still another object is the attainment of a method of forming fibers ofvery fine character adaptable for largescale commercial operationswherein large amounts of energy per unit of time are expended in theform of heat and extremely high velocities which have been foundnecessary to secure a high fiber yield, such state or operatingcondition being herein referred to as a high energy level.

Further objects and advantages are within the scope of this inventionsuch as relate to the arrangement, operation and function of thetrelatedelements of the structure,

to various details of construction and to combinations'of parts,elements per se, and to economies of manufacture.

and numerous other features as willbe apparent frorna consideration ofthe specification and drawing of a form? Figure 2 is a sectional viewtaken substantially on the line 22 of Figure I;

Figure 3 is a diagrammatic view illustrating an angular relationshipbetween orifices from which flow the fiberizing gaseous blasts;

Figure 4 is an elevational view illustrating structural features of oneform of apparatus for carrying outthe method of the invention;

Figure 5 is a side elevational view of the apparatus illustrated inFigure 4, one of the burner constructions being illustrated in section;

Figure 6 is a top plan view of the burner arrangement illustrated inFigure 4, showing one form of adjusting means for the burnerconstruction;

Figure 7 is a front elevational view of one of the burner orifices, theview being taken on the line 7--7 of Figure 4;

Figure 8 is a detailed sectional view through the blast orifice, theview being taken substantially on the line 88 of Figure 7;

Figure 9 is a diagrammatic view illustrating the path of movement of thebody of fiber-forming material under the influence of the gaseous blastsin the use of the apparatus shown in Figure 1;

Figure 10 is a semi-diagrammatic elevational view illustratingblast-forming means arranged in a generally vertical position whereinthe axes of the blasts are aligned with the respective blast-formingmeans;

Figure 11 is a side view of the apparatus illustrated in Figure 10;

Figure 12 illustrates another position of blast-forming means whereinthe mean axis of the crossed blasts is substantially horizontal;

Figure 13 is an elevational view of apparatus for producing crossedblasts moving in substantially parallel horizontal planes and showingmethods of feeding rods or primary filaments of fiber-forming materialinto the crossover zone of the blasts;

Figure 14 is a top plan view of the arrangement shown in Figure 13, theview being taken upon the line 1414 of Figure 13;

Figure 15 is a view similar to Figure 7 illustrating a modified form ofblast-directing, orifice, portions being shown broken away for purposesof illustration;

Figure 16 is a vertical sectional view taken substantially on the line16i6 of Figure 15;

Figure 17 is a sectional view through the orifice construction, the viewbeing taken on the line 17-17 of Figure 15;

Figure 18 is an elevational view showing another form of an orificeplate construction associated with a blastforrning means for directinggaseous blasts in crossover relation;

Figure 19 is a sectional view taken substantially on the line 19-19 ofFigure 18;

.Figure 20 is a bottom plan view of the blast orifice construction shownin Figure .18;

Figure '21 is an elevational view of a modified form of blast-formingmeans wherein dual blasts projected in crossover relationship emanatefrom a single chamber;

Figure 22 is a front .elevational view of the burnershown in Figure 21;

Figure 23 is an elevational view illustrating a modified structuralarrangement of blast-producing burners, par ticularly showing anadjustable mounting means for the burners;

Figure 24 is a side view of the burner construction and mounting meansillustrated in Figure 23;

Figure 25 is a top plan view of the arrangement shown in Figure 24;

Figure 26 is an elevational view illustrating a blast orificeconstruction especially adapted for use with a high velocity steam orair blast wherein the nozzle is formed with angularly disposedblast-directing slots;

Figure 27 is a sectional view of the arrangement illustrated in Figure26;

Figure 28 is a view similar to Figure 26 illustrating the blast orificemeans arranged in angular relation to pro vide crossed blasts;

Figure 29 is afragmentaryelevational view of a burner similarto thatshown in Figure 21 provided with a modified form-of orifice constructionforcstablishing crossed bl sts;

Figure 30 is a front view of the orifice construction illustrated inFigure 29; v v

Figure 31 is a partial sectional view through the burner constructionillustrated in Figure 29;

Figure 32 shows dual burners for producing an'gularly related blastsembodying the blast orifice configuration of the character shown inFigure 28; u

Figure 33 is a view similar to Figure 7 embodying an orificeconstruction having the operating characteristics of the type shown inFigure 28;

Figure 334 is an end view of the construction shown in Figure 33; p t IFigure 34 is a diagrammatic elevational view showing dual blastscrossing one another wherein the, blasts travel substantially in opposeddirections;

Figure 35 is a top plan view of the arrangement illustrated in Figure34;

Figure 36 isa top plan view of apparatus for producing a multiplicity ofblasts arranged to provide a plurality of crossover zones, and I Figure37 is an elevational view on a reduced scale of the arrangement shown inFigure 36. p

The principle of operation of the method of the present inventionresides in the establishment and utilization of forces acting alongdivergent loci upon flowable materials to fiberize, reduce, transform ordisintegrate the materials to fibers or other finely divided form orcondition. The method of the invention may be carried out by utilizinggases or other fluid mediums moving at high velocities and withsuflicient force or kinetic energy to attenuate, attrite or convertmaterials to fine fibers or other form of subdivision. The method isespecially suitable for transforming heat-softenable materials to'fibers through the utilization of high velocity gaseous blasts andparticularly heat-softenable mineral materials such as glass, slag,argillaceous rock or calcareous rock to fiber form and may also be usedto advantage in forming fibers from heat-softenable resinous materials.

The blasts may be formed of intensely hot gases moving under highvelocities such as the products of combustion resulting from burningcombustible mixtures in confined zones and the hot gases dischargedthrough restricted orifices to attain high velocities. Gases such assteam or compressed air may be utilized to advantage in carrying out thepresent method in a manner hereinafter described. V

Under certain operating conditions of the present method, thefiber-forming materials may be in a highly fluid condition and underother conditions, the material may be of a more viscous nature. Undercertain operating conditions, fiber-forming material may be fed into thefiberizing zone of the blasts in a substantially solid state.

While the method of the invention has been found to be especiallyapplicable in forming fine fibers from mineral materials such as glass,the principles of operation may be employed in transforming ordisintegrating other materials through the utilization of divergentlyacting forces in the manner hereinafter described.

Referring to the drawings in detail and first with respect to the formof apparatus illustrated in Figures 1 through 8 inclusive for performingor carrying out the steps of the method, the apparatus disclosed isparticularly adaptable for converting or attenuating bodies ofheatsoftenable, fiber-forming material to fibers. As glass in a moltenor softened state is readily converted to fibers by the method of theinvention, the apparatus will be described in connection with its usefor converting glass to fibers. The arrangement illustratedin Figures 1and 2 includes a forehearth 10 adapted to contain a supply of glass orother fiber-forming material in a heat-softened or flowable condition,the forehearth being connected with a suitable melting furnace (notshown). Disposed .be-'

neath the forehearth 10' is a feeder or bushing 12 having one or moreorifices or outlets located in a lower wall thereof from which flowstreams S of molten glass.

The glass streams are engaged by' forces operative in divergentdirections upon the flowing body of material or glass to transform it tofine fibers. 'In the form of the invention illustrated in Figure 1, theforces acting upon the glass streams are in the form of intensely hotgaseous blasts provided by products of combustion discharged frominternal combustion burners adapted to burn a fuel and air mixture. Theburners are indicated at 14 and produce blasts discharged throughorifices arranged at the forward extremities of the burners, thetemperature of the gaseous blasts being above the softening temperatureof the glass. The burner constructions and their mounting arrangementswill be hereinafter described in further detail.

The blasts discharged from the burners 14 engage the molten stream ofglass and by reason of the high blast velocities and the angularrelationship of the blasts, the molten material is attenuated,triturated or otherwise converted or transformed to fibers F which maybe confined within a hood 17 and collected at a suitablefiber-collecting zone 18. As illustrated in Figures 1 and 2, the fibersmay be deposited and collected upon the upper flight 20 of an endlessconveyor 21 supported by suitable rollers 23. The endless belt conveyorin the embodiment illustrated may be actuated so as to move the upperflight 20 in a left-hand direction as viewed in Figure 2 so that thefibers F which are continuously formed and collected upon the conveyor20 may be carried away from the collecting zone for further processing.Disposed beneath the upper flight 20 of the conveyor is a chamber 25which is connected with a suitable source of reduced pressure or suctionto facilitate the deposition and accumulation of the fibers upon theconveyor flight 20 and to aid in carrying away the heat of the blasts.

It may be desirable to treat the fibers during formation with 'alubricant or other coating as the fibers are formed. To accomplish atreatment of the fibers, there may be provided nozzles or applicators 27projecting interiorly of the forming hood 17 for directing thefibertreating lubricant or coating onto the fibers as they move throughthe forming hood.

For certain uses and purposes, it is desirable that the accumulated massor mat of fibers M be treated with a bonding resin or other suitablematerial for imparting mass integrity to the fibrous mat. Bonding resinof this 1 character may be sprayed or deposited upon the fibers by meansof one or more applicators 29 disposed exteriorly of the forming hood 17and adjacent the path of the moving mass of newly formed fibers.

One form of structure of blast burner arrangement of the invention andsupporting arrangementis illustrated in detail in Figures 4 through 8inclusive. This structure is inclusive of a frame 35 formed of basemembers 36 and a pair of upwardly extending columns 38 reinforced bystruts or braces 39. Secured to each of the columns 38 is a tubularstructure 41 within which is slidably disposed posts 42 which aresecured at their upper extremities to a platform member 44 in the formof an inverted channel member. 3

Means is provided for raising and lowering the posts 42 and platform 44.As shown, a horizontal shaft 46 is mounted in suitable journals carriedby the uprights 38 and is equipped with spur gears 48 enmeshed with theteeth of a rack 49 secured to each of the members 42. A handwheel 50 isprovided for rotating the shaft 46 and gears 48 to elevate or lower theplatform 44. A

suitable locking means (not shown) may be associated with the shaft 46and gears 48 to retain or lock the posts 42 in adjusted positions.

The platform 44 supports members 52 which are bored to receive rods orways 54. The rods 54 form support' ingmeans for a pair of carriages 56and 57. The car rrages are of substantially identical construction, eachbeing formed with a base member 58 provided with a depending portion 59bored to receive" the supporting shafts 54. The carriages are adapted tobe moved to.- ward and away from each other to vary the horizontaldistance between the burners 514. Each of the carriages is formed withvertically extending members 60 joined at their upper ends by plates 61.

Extending upwardly from the platform 44 are spaced members 63 havingopenings .to accommodate a shaft 65, the latter being arranged inparallelism with the shafts .54. The shaft 65 is formed with spacedenlarged threaded, portions 167, one of right-hand threads and the otherof left-hand threads, whichnrespectively cooperate with a third member69 securedtoxthe .upright. member 60 of each carriage. The ends of the.shaft 65 are provided with ,polygonally shaped .or squared portions 71adapted to receive a suitable crank or wrench for rotating the shaft 65.By reason of the right and left threads on shaft 65,; rotation of theshaft in one direction moves the carriages 56 and 57 toward each otherwhile rotation of the shaft in the oppositedirection moves the carriagesaway from each other.

Each of the carriage constructions .56 and 57 provides asupporting meansfor a trunnion or shaft 74 which extends through bearing members 75secured to the uprights 60 in order to provide a substantial mountingfor the trunnion 74, the latter being revoluble in the members 75.Secured to each trunnion or shaft 74 is a member or shaft 78, thetrunnions 74.and members 78 being formed at adjacent ends with flanges79 and 80 as shown in Figure 5. The opposite end of each of the members'78 is formed with a semi-annular portion 82 which cooperates with asemi-annular member 83 to support a burner construction.Eachisemi-annular portion 82 and a member 83 are secured together bymeans of bolts 84 to rigidly clamp and support the adjacent burner 14.Each of the trunnion shafts 74 is provided with .a worm wheel '86 drivenby a worm 88 *mounted upon a shaft 90 of squared or polygonallyshapedcross-section. The central openings in the worms 88am ofreciprocal shape in cross-section to that of the shaft 90 so that duringrelative movement of the carriages 56 and 57 along the supporting rods54, the worms 88 are relatively slidable along the shaft 90. Due to thenon-circular.drive connection between the drive shaft 90 and the worms88, rotation of the shaft 90 rotates the worms to drive the worm wheels86 and thereby effects corresponding rotation or angular positioning ofeach burner 14 about the axis of its supporting shaft 74. Rotation ofthe shaft to adjust the relative angular positions of the burners 14about the shafts 74 may be efiected by applying a suitable wrench orcrank to an extremity of the shaft 90.

As shown in Figure 5, each of the burners 14 is supported in thesemi-annular members 82 and 83 which are secured in clamping relationabout the burners by securing means 84. By backing off the nuts 85 onthe p bolts 84, the burners 14 may be individually rotated about theirlongitudinal axes to establish an angular relationship of the orificesfrom which the blasts emanate to establish the desired relative angularor crossover positions of the blasts.

The burners 14 are of the so-called internal combustion type adapted toburn a combustible mixture of fuel and air, the products of combustionbeing discharged from the burners to provide high velocity gaseousblasts. A burner of this general character is disclosed in Slayter andFletcher Patent No. 2,489,242. Each burner construction includes a metalshell which is lined nteriorly with suitable refractory material 97 asshown in Figure 8. The refractory material 97 surrounds and forms acombustion chamber 98 providing a confined zone within which combustiontakes place.

As shown in brokenlines in Figure 6, the rear wall 99 of the combustionchamber 98 is formed with a plurality of small apertures or passages 100through which a fuel and air mixture supplied ,to a manifold .101by aninlet pipe 102 is caused to enter the combustion chamber 98 by thepressure applied to the fuel and air mix-* ture. The fuel may be anatural or artificial gas or other combustible. The fuel and air areintroduced into the burners under a comparatively low pressure as, forexample, five pounds per square inch, although other pressures may beemployed if desired.

The products of combustion are discharged from the burners throughrestricted orifices to form intensely hot blasts of relatively highvelocities. As particularly illustrated in Figure 8, an orifice plate ormember 105 is secured to the front end of each burner and is providedwith an opening or passage 106 through which the gases are projectedfrom the chamber 98. The discharge orifice 107 is bounded by walls 108and 109 projecting downwardly and ata slight angle with respect to avertical plane. The walls 108 and 109 are shaped to register with thepassage 106 in the plate 105. The orifice construction is arranged to becooled by a suitable medium and includes a chamber 111 surrounding theorifice 107 and is provided with an inlet pipe 113 and an outlet pipe114. The pipes are adapted to convey a cooling liquid such as water or agas through the chamber 111 in order to reduce the temperature of theorifice walls.

The orifice construction is preferably removably secured to the burnerby bolts or other means passing through openings 115 in the plate 105.As shown in Figure 7, the orifice 107 is preferably of elongatedrectangular cross-section to provide a ribbon-like gaseous blast of highvelocity. The burning of a combustible fuel and air mixture within thechamber or confined zone 98 produces a blast of intensely hot gases, thetemperature of the gaseous blast or products of combustion being upwardsof 3000 Fahrenheit, .well above the softening temperature of the glassor other heat-softenable material which is transformed by the blastsinto fibers.

As illustrated in Figures .2 and 3, the orifices 107 are angularlydisposed and spaced apart so that the gaseous blasts are projecteddownwardly in generally parallel planes and at relative angularitiescausing them to cross each other in brushing relation at a zone at whichthe fiber-forming material or glass is introduced or delivered to beacted upon by the forces of the high velocity blasts. The burners 14 areadjustable to vary the distance between the blast orifices, to changethe relative angularities of the blasts and to move the blast-formingmeans vertically relative to the molten glass stream or otherfiberforming material. The burners 14 are adjusted in a verticaldirection by elevating or lowering the platform 44 carrying theburner-supporting means by manipulation of the handwheel 50 to rotatethe gears 48 and actuate the racks 49. By this means, the crossover zoneof the gaseous blasts may be adjusted toward or away from the streamfeeder 12 to obtain the most efficient point of delivery of thefiber-forming material into the blasts.

The horizontal spacing of the burners 14 and hence the extent or degreeof brushing contact of the blasts may be regulated by rotating the shaft7]. to move the burner-supporting carriages 56 and 57 in horizontaldirections. The relative angularities of discharge of the blasts fromthe burners 14 toward each other may be changed by rotating the shaft 90actuating the worms 88 and worm wheels 86 to effect rotation of theburners 14 about the axes of the trunnion shafts 74. By thisarrangement, the angularity at which the blasts are brought intobrushing relation may be adjusted to secure the most eflicient fiberformation.

The relative divergence of the gaseous blasts in establishing a desiredcrossover relation may be varied by changing the relative angularpositions of the orifices or blast-discharge outlets. As shown in Figure3, the angle A represents the divergent angle of crossover of theblasts. It has been found that a relative included angle of divergenceof the crossed blasts indicated by the angle A in Figure 3 of frorn.20to 35 has been :found to produce anions?" a satisfactory and desirablefibrous mat having a high percentage of fine fibers of a length suitableto impart resilience to the mat. Through the adjustable mountingarrangements for the burners 14, the latter may be positioned at variousangles of crossover for the blasts or the crossover zone at which theblasts brush or contact one another may be modified or varied asdesired.

The glass stream or streams S, which are comparatively large, passbetween the orifice constructions shown in Figure 1 and into theinfluence of the high velocity gas streams. Figure 9 is diagrammaticallyillustrative of the approximate locus or path of the molten glass streamas it moves from its vertical flow path into the influence of theblasts. From visual inspection, the stream appears to first follow awavering path and is then deflected laterally by reason of thedifferential pressures established by a the high velocities of theblasts and their divergent paths. Thestream of fiber-forming materialappears to be rotating or oscillating at a zone adjacent the outlets ofthe orifice constructions and resembles a mushroom-like formation 122, astate or condition probably caused by the divergently acting forces orforce couples acting on the glass stream as it enters the turbulenceexisting in the crossover zone 123.

' The tremendous yield of fine fibers, some of which are believed to bethe finest fibers ever produced, obtained from the practice of our novelmethod of fiber formation evidences a phenomenon of operation in theproduction of fibers which is completely different from any priormethods. Heretofore very fine streams of glass or fiberforming materialwere necessary to secure attenuated fibers by the steam blast method andcomparatively fine rods r filaments of about twenty-thousandths of aninch in diameter have been used with the hot blast methods to securefiber attenuation. The limitations of the amount of material fed to theattenuating blast necessarily restricted the fiber yield. v

The method of this invention is particularly adaptable to efiicientlyfiberizing large quantities of fiber-forming material in a given unit oftime resulting in a yield of very fine fibers many times that obtainablefrom other methods of hot blast fiber formation. One or more streams ofglass of a diameter of one-quarter of an inch or more are readily andefficiently converted to fine fibers by the forces utilized in themanner of the present invention.

We attribute the attainment of the phenomenal yield of fine fibers tothe novel principle of fiberization through the employment of crossedblasts of tremendous velocities and the utilization of large amounts ofkinetic energy.

.As the glass stream moves downwardly and enters the crossover zone intothe turbulence established through the brushing relation of the blasts,the violent forces in said zone act on the liquid stream to disrupt thestream and disintegrate it into a large number of liquid particles orbodies. This action takes place because the stream, being liquid, ismechanically unstable and under the influence of the force couplesestablished by the divergently-acting, high velocity forces, the streamis torn or broken up into particles. Thus there is established acoupling between the high velocity, divergently directed gaseous blastsand the glass stream whereby the forces act to break up the stream. Theparticles, bodies or fragments, being in liquid form, are virtuallyexploded by the forces into fine fibers or are attenuated to fibers bythe divergently-acting forces of the blasts. Through the utilization oflarge amounts ofkinetic energy by burning substantial quantities ofcombustible mixture in the burners and discharging the intensely hotgases of combustion at high velocities and delivering the glass in ahighly fluid condition to the crossover zone, the high temperatureworking range is increased so that attenuation of the particles occursthroughout the working range with the glass remaining in fluid form.Hencethe bulk of the particles are drawn percent by weight of thefibrous end product.

or attenuated to fibers of a fineness not heretofore obtainable byconventional methods.

While it has been found that a small portion of the glass delivered tothe blasts may not have been converted to fiber form, a substantialamount of such unfiberized residue in the fibrous end product is in theform of flakes or bodies of minute dimension having planar surfaces orfacets. Some of the unfiberized material is in the form of fine dustwith a minor amount of small shot or pellets present in the end product.Heretofore the unfiberized component of a fibrous mass appeared in theform of shot or pellets in those fiberizing processes of a commercialcharacter employing steam or air blasts. By actual tests, it has beenfound that in end products of fibrous mineral material formed by steamor air blast methods, the shot or pellet content may be upwards ofthirty-five or forty In the end product formed by the method of thisinvention as carried out through the use of the apparatus illustrated inFigures 1 through 9, the unfiberized material in the end product may bereduced to less than fourteen percent by Weight of the complete productwith the bulk of unfiberized material appearing in the forms of dust orminute flake-like particles.

The avoidance as far as possible of unfiberized material in the endproduct is extremely important for several reasons especially where thefibrous product is used for heat insulation or acoustic purposes. Theunfiberized material performs no useful function whatever and increasesthe manufacturing and material costs of the fibrous products as well asthe transportation costs because of the added weight of glass inunifiberized condition.

While the action of the many forces operating in the blasts inconverting flowable material to fiber form or fine particle size may notbe fully comprehended, the actual operation of the apparatus in carryingout the method results in the production of a fibrous end product havinga high percentage of fine fibers and a low constituent of unfiberizedparticles. The formation of shot or pellets is greatly reduced in theprocess. The relative angularity or included angle of divergence of theblasts has a material bearing upon the fineness of the fibers producedand the amount of unfiberized residue in the end product as shown by theresults of actual operations hereinafter described.

From actual tests it has been found that extremely fine fibers are mostsatisfactorily formed from glass while the latter is in an extremelyfluid condition. This may possibly be attributed to the fact that glassat a very high temperature remains in a fluid or fiber-forming conditionfor a longer period of time while it is being acted upon by the forcesof the high velocity blasts. If fibers of increased diameters aredesired, the temperature of the glass may be lowered to increase theviscosity of the glass. The character of the fibers may be varied bymoving the blast-producing means or burners closer to or farther awayfrom the source of the fiber-forming material. By proper correlation ofthese and other operating factors, the method provides for themaintenance of an effective and efiicient control over the character andsize of fibers produced.

The desired relative positioning of the blasts, their angles ofincidence and their angles of divergence or crossover may be determinedthrough the adjustable mounting means or devices associated withblast-producing means. The burners 14 may be elevated or lowered withrespect to the glass feeder 12 by manipulation of the handwheel 50, thegears 48 enmeshed with the racks 49 serving to elevate or lower theburner constructions supported upon the table 4.4. The angle ofincidenceof one blast toward the other may be varied by rotating the burnersabout the axes of shafts 75. This adjustment is attained by afiixing asuitable tool to one end of the squared shaft and rotating the shaft tocauserotation of-the worms 88,"

"11 worm wheels 86 and shafts. 751and7,8= directlysuPPQrtingt, theburners or blast-producingymeans 14; I a v The juxtaposed" relationshipoftthe blastson their 'hor1- zontal. spacing may be varied by. moving tthe, burners toward or away) from. eachtothert by; applyinga suitable,tool to the shaft 65and rotating thetsamel inthe'gproper direction tothread the. nuts 69 along the; shaft. toEmove theburnerassembliestalongttheir: aligned horizontal axes.-. The amount ofrelative angularity ordivergeuceuofsthe blasts may be adjusted orvaried. by manipulating the clamp screws 84 toreleasethe clamps 82. and83 surrounding the burner housings. The burners. may then be manuallyrotated about their horizontal axes until the proper lateral angularityor divergence of each blast is obtained with respect to the other. The?relative angular positions of the burners may be maintained by drawingthe clamps 82 and 83 into frictional contact with the cylindrical outersurfaces of the burner housings.

The blasts in their opposed relation are preferably projected insubstantially parallel planes but with a sufli' cientangle of incidenceso that the gas streamstcontact or brush one another at the crossoverzone into which the fiber-forming material may be deliveredto be actedupon or converted to fiber form. While the blasts are directed insubstantial parallelism in crossover or X-like relation,

brushing contactof the surfacelayers of the gas streams is establishedwithout appreciable intersection so as to avoidv interference orinterruption of the individualpaths of the streams and maintain highblast velocity necessary to secure efiicient attenuation or formation offibers.

The fiber-forming material is preferably introduced at the zone ofcrossing of the blasts where it issubjected. to divergently actingforces attaining the phenomenal efficiency of attenuation or fiberformation of this process. The fiber-forming material moving into thezone of turbulence between the blasts is disintegrated or separated intorelatively small components, most of which are exploded, attenuated orotherwise converted .by the high velocities to fiber form. Only arelatively small proportion of the fiber-forming material remains inunfiberized condition in contradistinction to the high. percentage ofshot-like or pellet formations of unfiberized material occurring in theend products produced by conventional blast processes where the blastsare not directed in crossing relation.

The method of the invention carried outthrou'gh the utilization of theapparatus illustrated in Figures .1 through 9 results in a product inthe form of a mass o'r rn at of haphazardly arranged fibers. whereinsubstantial. quantities of the fibers in the mass are of extremely finesize. Tests of fibers from three sample runs of the apparatus showed thefollowing average fiber diameters ascertained through the use of theelectron microscope:

In these and other groups of fibers produced by the method of thepresent invention, it was found that fiber diameters ranged from onemillionth of an inch to twentyfour hundred thousandths of an inch with alarge portion of the fiber diameters being less than one hundredthousandth of an inch.

Another factor that appears to be of vital importance in securingefiicient and economical production of fibers in the process is theestablishment of operating conditions involving a so-called high. energylevel. It has been found by tests that a high blast velocity ofcomparatively small volume of gas does not result in efficientattenuation of fiber-forming material.- Efiicient andeconomicaloperation is dependent in a large measure, upon the employment of gaseous blasts in crossover relation wherein comparatively largequantities 01' volumes of gas are provided in forming the blasts movingat-high velocities in order to attain' ahighenergy level. Thefollowingare typical t examples'of actual operatingconditions in carrying out theprocess of the invention. The apparatus included two internahcombustionburners of the type shown at 14 inrFigure 1- equipped' withrectangularly shaped orifices of the character shown in Figures 7 and 8,each orifice being-.threeinches longand seven-sixteenths of an inchinwidth. The'burners' were adjusted to secure a combined combustion rateof fourteen hundred and fifty cubic feet of fuel gas per hour under aninput pressure of four and three-quarters pounds at the manifolds of theburners. The blasts established by these operating conditions produced ahigh yield of fine fibers from large.

streams of molten glass.

By equipping the burners with rectangularlyshaped orifices, each orificebeing three and three-quarters inches in length and one-half of an inchin width, the burners consumed a total of two thousand cubic feet offuel gas per hour under an input pressure at the manifolds of four.

and three-quarters pounds per inch. The blasts provided under theseoperating conditions resulted in a high yield of fibers which are on theaverage of slightly smaller diameter than those obtained under thefirst-mentioned operating conditions, probably due to the increase inblast energy expended. The operating conditions abovedescribed result inthe attenuation or conversion of glass batch to fibers at rates of onehundred pounds or more per hour.

Theangle of divergence of the crossing blasts has a; 'defimtetefliectupon the amount of unfiberized glass in the end product appearing in theform of flake-like particles. For example, actual tests under operatingconditions of the character described gave the percentage by weight ofunfiberized material when the blasts were.

crossed at the specified included angle of divergence as listed below:

Percent by Weight of Unfiherized Glass in Included Angle of Divergenceof Blasts From the foregoing, it will be seen that increasing thedivergence angle from 17 20 to 30 20 resulted in a substantial reductionin the amount of glass in an unfiberized state in the end product. Thetemperature of the molten glass at the stream-feeding means ismaintained at or abovev 2500 Fahrenheit in order to deliver' theglassin'a highly fluid or fiowable condition into the" Moreover, thefiber-forming operation of the present method is'not of a criticalnature as the high velocities and high energy level of the dual blastsin crossed relation 1 provide divergently acting forces and the twistingor swirlingforccs in the crossover zone that are adequate toconvert'large quantities of fiber-forming material to comparatively finefibersin. a given unit of time. Hence with ample blast velocities and arelatively largc amount of energy available as-kinetic forces in theblasts, .a single stream of'fiber-fortning material of substantial sizeor a plurality; of streamsmay he ted or deliveredinto the zone ofcontact orcrossoven of the blasts-andsuccessful fiber End Productformation obtained avoiding critical operating' factors and precisionadjustments that are attendant the commercial utilization of otherfiber-forming processes adapted to produce fibers .of a comparablenature and size. t

Figures 10 and 11 illustrate a'form of apparatus for carrying out themethod of fiber formation wherein the ber 127 terminates in a restrictedorifice 130 of elongated character arranged to project a blast 132 in adownward, substantially vertical direction. The blasts provided by thegaseous streams emanatin'gfrom the burners 125 are intensely hot gasesof combustion which, by reason of their great expansion u'nder'theintense heat existent in the chambers 127 and the restricted orifices130, are projected from the burners at tremendously high velocities.While the gaseous blasts from the burners move downwardly, theyare'preferably inclined slightly toward each other as indicated inFigure so that the juxtaposed surfacezones of the blasts brush togetheror contact each other as they move in crossover relation as illustratedin Figure 11. The brushing contact of the gas streams at the zone ofcrossing tends to cause the gases to thereafter move in substantialparallel planes in divergent directions. The stream or body of materialS is directed between the blasts at the zone of crossover as shown inFigure 10 and the forces of the blasts acting in divergent directionsconvert the material to fiber form.

It is to be understood that the angularity of crossover of the blastsmay be varied, and it is found that as a general rule increasing theangularity of the blasts forming the crossover produces finer fibers onthe average with a reduction of the material in the end product inunfiberized form as pointed out in the description of operation of theapparatus shown in Figures 1 through 8.

While it has been found preferable to utilize the crossover blastsformed of intensely hot burned gases discharged through restrictedorifices at high velocities, it is to be understood that a steam blastor an air blast may be utilized as the force for converting material tofibers in a manner hereinafter described.

Figure 12 illustrates an apparatus for carrying out the method whereinthe blasts cross each other as they travel at divergent angles relativeto a horizontal plane. In this form the burners 125' are disposed in anangular relation above and below a mean horizontal plane. The blasts maybe formed by burned gases projected through restricted orifices of theburners 125 at high velocity in crossed relationship and utilized forthe fiber-forming phase of the method.

' Where the gaseous blasts are of an intensely hot character above theattenuating temperature of glass or other heat-softenable, fiber-formingmaterial, such blasts may be utilized to convert substantially rigidfilaments or rods of fiber-forming material into fibers. Anexemplification of the method of feeding or delivering rods orsubstantially rigid filaments is illustrated in broken lines in Figure12. When the method is employed in this manner, one or more rods 135 maybe fed between the blasts into the crossover zone by feed rolls 136 orother suitable means at a rate whereby the tips of the filaments will becontinuously softened and acted upon by the blasts to convert thematerial to fibers. The fibers may be collected upon an upwardly movingconveyor belt (not shown) or they may be directed into a suitablecollecting chamber (not shown).

Figures 13 and 14 illustrate a crossover blast arrange- 1d ment inconjunction with the feeding of a rod or sub stantially rigid body ofheat-softenable, fiber-forming material into the crossover zone of theblast at right angles to a mean or median plane bisecting the includedangle of divergence of the blasts. In this arrangement the burners aredisposed in positions similar to the burners of Figure 12, and a rod orrigid body 138 of fiberforming material is directed into the crossoverzone of the blasts from a substantially vertical position. The material138 is fed or delivered to the blasts by means of feed rolls 1419 orother suitable means. The rigid body 138 may be preformed from a streamof the material moved through a distance sufficient to congeal thematerial. The intense heat of the blasts 139 softens the tip of the body138, the forces. of the blasts converting the softened material tofibers.

Figures 15 through 17 inclusive illustrate a modified form of burnerorifice of the general character shown in Figures 7 and 8, the orificeconstruction being provided with guide means for imparting an angulardirection to the blast. In this form of the invention, the plate 1115supports an orifice construction provided with a plurality of tubularpassages forming a blast-discharge means. The orifice construction isformed with outer walls providing a chamber 111 through which water orother cooling medium may be circulated to control the temperature of theorifice walls.

The plurality of spaced tubular passages 145 is arranged in substantialparallelism and at an angle with respect to the vertical of from 10 to15 in order to impart an angular direction to the gases flowingtherethrough forming a blast. The orifice construction secured to theopposing burner (not shown) is provided with tubular passages disposedat an oppositely directed angle. The lateral spaces 146 between thetubular passages provide for intimate contact of the cooling fluid withthe Walls to facilitate more uniform cooling of all portions subjectedto the intense heat of the gases.

Thus burners 14 of the character shown in Figure 1 having orifice platesof the construction disclosed in Figures 15 through 17 are adapted toprovide angularly divergent blasts in crossover relation without specialadjustment ofthe burners about their longitudinal axes. If a greater orlesser angularity between the blasts is desired, the burners providedwith the orifice construction of the type illustrated in Figures 15through 17 may be rotated about their axes to secure different angularrelationships of the blasts.

A further form of apparatus for carrying out the method of the inventionis illustrated in Figures 18 through 20. In this form, a single burner150 of a construction similar to one of the burners 14 is utilized forproducing divergent blasts of burned gases. The burner is provided withan orifice configuration whereby the gases discharged from the burnerchamber are directed through two series of openings providing two groupsof gas streams moving in crossover relation for transforming material tofibers.

The blast-discharge and directing means is inclusive of a base, plate152 and a second plate 153 spaced outwardly therefrom. The plates 152and 153 are joined by a continuous lateral or side Wall 154 providing achamber 156 adapted to accommodate a circulating cooling fluid such asWater introduced through an inlet pipe 158 and carried away through adischarge pipe 159. The plates 152 and 153 are provided with elongatedopenings to receive and accommodate blocks or members 161 and 162 whichare welded to the plates as at 163.

The member 161 in the illustrated embodiment is formed with a series oforifices or passages 165 preferably of circular cross-section Whicharedisposed in substantial parallelism but are downwardly angularlyinclined with respect to a horizontal plane or longitudinal axis of theburner 150. The openings 165 in the member 161 are arranged in spacedrelation in a row extending upwardly and laterally with respect to avertical plane extending through the center of the plate 153 and normalto the plate. The member 162 is formed with a similar row of orifices orpassages arranged in spaced parallel relation but askewed or angularlydirected upwardly with respect to the longitudinal axis of the burner.The group of openings 167 extend upwardly and laterally relative to avertical plane through the center of the plate 153. The angularlydivergent rows of passages provide a generally V-shaped gas dischargeorifice configuration. The passages of one row are slightly inclinedtoward those of the other row as shown in Figures 18 and 20.

As therows or groups of openings or passages 165 and 167 are disposed ina converging direction, the high velocity blasts formed by the gases ofcombustion in the burner projected through the orifices form in effectat the crossover area a V-shaped configuration or trough into which thebody or stream of fiber-forming material S may be directed in the mannershown in Figures 18 and 19. As the forces of the two blasts engage thestream of material S substantially at the crossover zone, the materialis heated by the intensely hot gases of the blasts and converted ortransformed into fibers by the attenuating or attritive action of theblasts.

The plate 153 is formed with a wall portion 155 extending a substantialdistance above the orifices and 167 constituting a baffie or abutmentcausing the induced air stream established by the high velocities of thegases of the blasts to pass over and around the portion 155. Bydirecting the air stream around the plate 153, a reduced pressure is setup adjacent the obverse face of the plate 153 in the zone immediatelyabove the gaseous blasts flowing from orifices 165 and 167. This reducedpressure zone influences the stream S of glass or other fiberformingmaterial to flow into the zone between the blasts immediately adjacentthe face of the plate at the initial stage of the crossover formation.By reason of the pressure differential tending to keep the stream closeto the plate 153, the divergently directed and disruptive forces of theblasts cause the extremity of the stream of fiber-forming material to beattenuated or converted to fibers. The efficiency of fiber attenuationis facilitated as the stream 8 is influenced or biased by the pressuredifferential toward the plate 153 providing a snubbing point or inertiafactor from which the fibers may be drawn or attenuated from theadvancing tip of the stream by the forces of the blasts. Thus in thisform of the apparatus the velocity of the blasts initiates theattenuation of fibers from the extremity of the stream and thedivergently directed forces of the blasts at the crossover zone set uptwisting or compound forces augmenting the attenuation or conversion ofthe material to fine fibers as it is carried along by the blasts.

The orifice construction illustrated in Figures 18 through 20 may beemployed for the projection of other types of gases such as steamer airundercomparatively high pressures to establish blasts of high velocitiestraveling in crossover relation to effectively convert flowable materialto fibers.

Figures 21 and 22 are illustrative of another form of apparatus forcarrying out the method of the invention. In this type of apparatus asingle burner 170 is configurated to produce dual blasts of burned gasesprojected in crossover relation. The burner 170 is formed with a chamber172 within whicha mixture of fuel and air is burned which is supplied tothe chamber through a manifold 173 from a mixture inlet pipe 174. A wall.175 is disposed between the manifoldand the combustion chamber which isprovided with a plurality of small passages to admit the mixture intothe chamber 172 and forms a fire screen to avoid ignition of the mixturein the manifold 173.

The forward portion of the burner 170 is provided with a member formedwith a pair of openingsor orifices 177 and 178 preferably in therelationship illustrated in 16 Figure 22. It should be noted that theorifices are of narrow elongated configuration so that the intensely hotexhaust or burned gases of combustion are discharged therethrough atrelatively high velocities. As will be seen in Figure 22, the orificesare disposed in offset relation with respect to'a vertical central planethrough the a burner and are arranged at a slight angle of convergence.

The angularity of the side walls of the orifices is such as to directthe blasts toward each other so that they contact or brush each other atthe crossover zone, the blasts traveling in substantially parallelplanes as they leave the crossover zone. As shown in Figure 21, theblastdischarge orifices are arranged so as to direct the blasts B and Bin crossover relation and in divergent directions as they leave thecrossover zone. The stream or body S of fiber-forming material may bedelivered between the blasts into the crossover zone wherein the forcesof the blasts attenuate, triturate or otherwise convert the material tofiber form. The fiber-forming material may also be delivered into thecrossover zone as an elongated rigid or semi-rigid body, the advancingextremity of which is softened or reduced toflowable consistency to adegree that the material is readily acted upon by the blasts andconverted to fibers.

Figures 23 through 25 inclusive illustrate a modified form of apparatusfor carrying out the method of the invention utilizing a dual burnerarrangement having a particular adjustable mounting or supporting means.Two burners and 186 ofsubstantially identical construction are supportedupon a universally adjustable mounting structure adapted to facilitatevarying or changing the angular or interrelated positions of the burnersand hence predetermining the relation of the blasts to modify theoperating conditions as desired.

The burners 185 and 186 in the illustrated embodiment and their mountingconstructions are carried upon a shaft or member 188. As the burners andthe individual mounting means therefor are of identical construction, adescription of one will suffice for both constructions. Each of theburners is provided with a skeleton supporting structure formed of aplate 190 provided with G- shaped members 192 which partially embraceand clamp the burner housings, as particularly shown in Figures 23 and25, to provide supports for the burners. The plates 190 are bored andthreaded to receive screws 194 which may be drawn up to securely retainthe burner in the adjacent clamping members 192.

Each of the plates 190 is secured to a tenon 196 formed upon a stubshaft 197, the stub shaft passing through a bore formed in a bossportion 199 of an arm 200. An opposite end portion of the arm200 extendsinto a bore formed in a block'or fitting 202, the latter being formedwith a transverse bore to be slidably received upon the supporting shaft188. Each block 202 is provided with a clamping screw 204 for securingthe block to the member 200-and a second clamping screw 205 for securingthe block 202 upon the shaft 188.

The burners are individually adjustable about the axes of the shafts 197and are adjustable about the axes of the arms 200 by rotation of thelatter relative to the fittings 202. The'boss portion 199 of each member200 has a threaded opening to receive a clamping screw 261 for securingthe adjacent burner in fixed angular relation with respect to the arm200.

Each of the plates 190 is equipped with a graduated or calibrated scale207 and each boss portion 199 is equipped with an index arm or indicator208 for cooporation with the graduations on the scale .207. Thegraduations represent degrees of the relative angular position of theburner about the axis of itsjsupporting shaft 197.

Mounted upon each member 200 is a collar 210 secured in adjustedposition by a clamping screw 211. One face of each block or fitting 262is provided with a series of graduations 2112 for indicating theinclination of the burners toward each other as they are adjusted aboutthe axis of the arm 200. Each collar 210 is equipped with an.

2 202 along the shaft 188. The shaft 188 may be carried by a suitablesupporting frame (not shown).

The mounting arrangement for the burners 185 and 186 provides forindividual or independent angular adjustment of each burner about theaxis of its respective supporting shaft 197. To'obtain a crossing of theblasts B and B, the burner 185 may be adjusted in one angular positionas indicated in broken lines in Figure 24 and the burner 186 angularlyadjusted in the opposite direction to direct the blasts in crossoverrelation. In order to cause the blasts at the zone of crossover to brusheach other, the burners maybe inclined through a slight angle wherebythe blasts B and B bear toward each other to establish contact of theadjacent gases of the blasts at the crossover zone. This adjustment ofthe burners may be attained by releasing the clamping screws 204 androtating the arms 200 relative to the fittings 202, the desiredangularity from a vertical position being indicated by the position ofthe indicator 214 relative to the graduations 212. When the properregulation or adjustment of the relative positions of the burners isobtained, the clamping screws 201 and 204 may be drawn up to secure theburners in fixed positions.

The dual burner assembly as shown in Figure 23 is disposed beneath afeeder 216 from which a stream of glass S or other fiber-formingmaterial is permitted to flow or be delivered into the crossover zone ofthe blasts. If desired, the fiber-forming material may be in the form ofa rigid or semi-rigid rod which may be fed into the blasts of intenselyhot burned gases of the blasts B and B, the heat of the blasts beingsufficient to soften the extremity of the advancing rod and theforces ofthe blasts under high velocities acting in crossed or divergent relationserving to efiectively convert or attenuate the softened material tofibers.

It is to be understood that the apparatus illustrated in Figures 23through 25 is especially adaptable to form fibers by hot blastsemanating through restricted orifices associated with the burners. Ifdesired, high velocity blasts of steam or air under pressure may beprojected through the orifices in crossover relation to engage a streamof heat-softened or molten fiber-forming material to convert the same tofibers. Through the universal mounting arrangement for each individualburner, various angular positions of the burners may be had to vary orregulate the character and relative position of the crossover zone andthe angularity of the attenuating forces of the blasts to establishdifferent operating conditions for obtaining various types and sizes offibers as desired for particular purposes.

Figures 26 and 27 illustrate a fiber-forming apparatus embodying theprinciples of the present invention and especially adapted to utilizeblasts of steam, compressed air or the like in crossover relation forengagement with a plurality of streams of fiberforming material. Theapparatus is generally similar to that employed for attenuatingheat-softened glass to form fibrous wool modified to carry out themethod of the invention. The apparatus includes a feeder 220 forming apart of a forehearth 221 associated with a glass-melting furnace (notshown). The feeder 220 is provided with a plurality of spaced orificesarranged in one or more rows in the bottom of the feeder through whichstreams of molten glass are delivered from the forehearth. Disposedbeneath and adjacent the feeder is a blower construction 224 whichincludes a member 225 formed with manifolds or chambers 226communicating with horizontal passageways 228 adapted for discharginggases under pressure to provide high velocity attenuating blasts. 'Theblower construction 224 illustrated is especially configurated for theutilization of steam as a fiber-attenuating force.

The member 225 is formed with a central passageway 230, the opposinginner walls of the member 224 being slanted in a converging direction asshown in Figure 27. Guide or baffle plates 232 and 233 are attached tothe inner opposed walls or faces 23 3 of the member 225 and are attachedto said faces by means of screws 236 as shown in Figure 27. The member225 is of elongated character as shown in Figure 26 and the slot orpassageway 230 formed between the plates 232 and 233 extendssubstantially the full length of the block. A construction of thisgeneral character is illustrated in Slayter Patent 2,206,060.

The baffle plates are formed with narrow channels or grooves which arespaced at short intervals throughout the length of the plates andalternate with narrow ribs 221 between the grooves. The grooves 238formed in baifie plate 232 are slanted downwardly and in a righthanddirection as viewed in Figure 26, while the grooves 239 in plate 233 areslanted downwardly and in a lefthand direction as viewed in Figure 26.When the plates 232 and 233 are secured to the member 225 in the posi-'tion illustrated in Figure 27, the grooves are in registry with thepassages 228 and extend downwardly below the passages, the groovesproviding a multiplicity of small, downwardly extending, angularlydisposed nozzles, passageways or orifices through whichthe steam orother gas under pressure is projected.

As the ribs bear against the inner faces of the member 225, the groovesare thus separated so that a multiplicity of separate channels areprovided so that gases are projected therethrough from the grooves ineach plate to form a high velocity blast of relatively thin, sheet-likeshape. The grooves 238 in the baflie plate 232 direct the gases in aright-hand direction as viewed in Figure 26, while the grooves 239 inthe plate 233 direct the long thin blast of gases downwardly and in aleft-hand direction.

It should be noted that while there is a slight convergence of the innerwalls 234 of the passage 230, the blasts travel downwardly insubstantial parallelism yet have a brushing contact with each other. Byreason of the non-intersecting paths of the blasts and the relativeangular positions of the channels 238 and 239, the blasts are caused tocross each other in a zone beneath the blower 224 which is hereinreferred to as the crossover zone.

The plurality of streams S of flowable fiber-forming material isdirected from the feeder 220 into the crossover zone of the blasts. Thehigh-pressure steam or air blasts move in divergent directions as theyleave the crossover zone, and under the influence of the divergentlyacting forces and force couples set up by the high velocities of thegaseous blasts in crossing each other in brushing contact, thefiber-forming material delivered into the crossover zone is attenuated,triturated or otherwise converted into fiber form. The included anglebetween the nozzles or channels 238 and 239 may be from 20 to 35 forsuccessful operation, and an included angle of 24 has, in actualoperation, given very satisfactory fiber formation.

The fibers produced are of longer and finer character than thoseheretofore produced by the steam blast method such as the methoddisclosed in the Slayter and Thomas Patent No. 2,257,767. The fibersformed by the method of this invention are .of an average length greaterthan those produced by the steam blast methods of conventional charactershown in Patent 2,257,767, provide fibrous mats that are more resilientand by reason of the finer fibers, the mats are of low density. Anotheradvantage attendant the attenuation of fibers through the use of theapparatus shown in Figures 26 and 27 lies in the fact that a largerproportion of the glass batch is converted to fibers with acorresponding decrease in the amount of. unfiberized material in the endproduct,

Heretofore the unfiberized constituent of the fibrous mass was presentin the form of spherically shaped pellets or shot. Through theutilization of the method of steam or air blasts in the apparatus ofFigures 26 and 27, a much lower content of glass is present in shot orpellet form and a substantial portion of unfiberized material appears inthe form of flakes or non-spherical configurations.

Figure 28 illustrates a modified form of the orifice plate, arrangementshown in Figure 26 adapted for use in attenuating or. convertingfiowable material to fibers through the use of steam or air blasts. Inthis form the individual blower units v225 are provided with the orificeplates 248 and 249 which are inclined relative to each other and crossedin the manner illustrated in Figure 28. The serrations forming theorifices or openings in the plates 248 and 249 are disposed at rightangles to the respective longitudinal axes of each orifice plate, and bydisposing the plates in crossed or angular relation, the blasts areprojected in crossover relation without especially configurating the gaspassages in the plates in acuteangular relation. In this form ofapparatus, the streams S of fiber-forming material pass through thespace or gap between the orifice plates 243 and 249 into the crossoverzone of the blasts where the material is converted into fine fibers.

The arrangement illustrated in Figures 29 through 31 involves theformation of ,angularly converging blasts projected in crossoverrelation, this form of apparatus having particular utility in theformation of fibers from glass or other fiber-forming material whereinan intensely hot, high velocity blast is utilized to convert thematerial to fine fibers. The arrangement more especially involves anorifice construction wherein the crossover blasts are formed of gases ofcombustion from a single burner chamber which are discharged throughorifices having blast-guiding surfaces arranged to cause the gaseousblasts to cross over and provide the divergently acting and compoundforces for converting fiber-forming material to fibers or reducingmaterial to a finely divided state. This form of apparatus embodies ablast-guiding orifice means for conveying the gases of the blasts to thecrossover zone, the means being shaped to obtain the maximum velocity ofthe gases at the crossover zone and secure a high efficiency of materialconversion or attenuation.

The burner chamber illustrated may be of the general character shown inFigure 21 and embodies a shell 260 having a refractory-Walled interiorforming a combustion chamber 262, a combustible mixture of gases beingadmitted to a manifold 264, the mixture passing through openings 265 ina wall 266 separating the combustion chamber from the manifold, theperforated wall 266 serving to avoid pre-ignition in the manifold.

The forward or nose end of the chamber is provided with an orifice plateor member 267 having orifices or gas discharge openings 270 and 271respectively formed in angularly projecting bosses 274 and 275 formed onthe plate. It should be noted, as particularly shown in Figure 31, thatthe guide walls 276 and 277 of the orifice 271 are inclined downwardlyand the walls 278 and 279' are inclined upwardly causing the blasts ofgas to pass each other at a crossover zone designated 280. The plate ormember 267 is formed with cooling chambers or passages 268' having inletand outlet pipes 268 and 269 for conveying water or other cooling fluidthrough the chambers 268' to eifectively cool the plate. It has beenfound that the point or zone of highest gas velocity of a blast is atits point of discharge from an orifice. In the apparatus shown inFigures 29 through 31, the guiding wall 276 directing the one blast in adownwardly direction and the Wall 278 guiding the upwardly directedblast terminate at zone 285 at which zone the gases of the individualblasts are adjacent the crossover zone. Thus the highest velocities ofthe blasts exist as the gases leave the guide walls of the orifices andmove into crossover relation. The stream of fiber-forming material S isdeell) livered into the crossover zone of the blasts by feeding thematerial in a path adjacent the terminus of the orifice wall 276. Inthis manner the fiber-forming material is fed into the zone of thegreatest forces of the blasts, the gases of the blasts being atsubstantially their highest temperature and velocity providing for mostefficient fiber attenuation or formation.

Figure 32 is illustrative of apparatus for converting material to fiberform or a finely divided state utilizing the constructional features andprinciples of operation of the arrangement shown in Figures 29 through31. In this form two individual burners or combustion chambers areemployed, each provided with a restricted orifice for the passage ofgases to produce the blasts. In this arrangcnient burners 290 and 292are arranged in downwardly converging relation and disposed at anincluded angle at which it is desired to cross the blasts. The lower ororifice end of each burner is provided with a projecting portion 294within which is formed the re stricted orifice or outlet through whichthe gases of combustion from the burners are discharged at highvelocity. Thus the outer zone of each blast is prevented from expandinguntil the gases are close to the crossover zone so as to obtain thehighest velocity of the blast at the zone into which the fiber-formingmaterial is delivered. As illustrated in Figure 32, a stream S of glassor other fiber-forming material in a highly fluid state is directed intothe crossover zone 296 so as to obtain a high efficiency of attenuationof material to fiber form or the conversion of material to a finelydivided state or condition.

Figures 33 and 33:: are illustrative of a modified form of orifice plateof the character shown in Figure 7 which may be employed to advantagewith the arrangement of burners shown in Figure l. The orificeconstruction is inclusive of a member 300 to which is assembled plates302 and 303 spaced to form an elongated orifice through which gases ofcombustion from a burner (not shown) may be discharged at highvelocities. As particularly shown, the forward edge 3tl5 of theoutermost plate 363 is angularly disposed and the wall portion 306bounding one edge zone of the blast is of greater length than the wallportion 307 at the opposite edge zone.

By this construction the gases at the outer edges of the blasts areconfined for a greater distance and hence their highest velocity is asclose as possible to the crossover zone. Thus burners of the charactershown at 14 in Fig ure 1 equipped with orifice constructions of the typeshown in Figures 33 and 33a provide for maintaining high velocities forthe gases as near as possible to the crossover zone. The plates orelements forming the passage for the gases are constructed to providechambers of the character shown in Figure 8 through which a coolingfluid such as water or the like may be circulated, the water beingconducted into and away from the cooling chambers by inlet and outletpipes 309 and 3112.

Figures 34 and 35 illustrate semi-diagrammatically an arrangement ofblast-forming means disposed so as to direct the blasts in substantiallyopposite directions or at a wide or obtuse angle of divergence and incrossover relation. The burners 315 and 316 are mounted in generallyopposed relation, the angle of divergence being indicated at C in Figure34. As shown the blasts are projected axially of the burners and in sucharrangement the angle C represents the angle of divergence of the blastsB and B. As represented in Figure 35, the blasts do not intersect butpass each other in brushing relation at the crossover zone. A streamorbody S of fiberforming material such as glass is delivered into thecrossover zone and subjected to the forces of the high velocityblasts'to disintegrate or attenuate the material into fibers with aminor amount of the material being reduced 'to fine flake-likeparticles. The burners are spaced laterally as shown in Figure 35 asufficient distance to cause the blasts to cross in brushing relationand divergently ar-

